|  | // RUN: %clang_tsan %s -o %t | 
|  | // RUN: %run %t 2>&1 | FileCheck %s --implicit-check-not='ThreadSanitizer' | 
|  |  | 
|  | #include "dispatch/dispatch.h" | 
|  |  | 
|  | #include <stdio.h> | 
|  |  | 
|  | long global; | 
|  |  | 
|  | int main(int argc, const char *argv[]) { | 
|  | dispatch_semaphore_t done = dispatch_semaphore_create(0); | 
|  |  | 
|  | dispatch_queue_t queue = | 
|  | dispatch_queue_create("my.queue", DISPATCH_QUEUE_CONCURRENT); | 
|  |  | 
|  | dispatch_source_t source = | 
|  | dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue); | 
|  |  | 
|  | dispatch_source_set_timer(source, dispatch_walltime(NULL, 0), 1e9, 5); | 
|  |  | 
|  | global = 42; | 
|  |  | 
|  | dispatch_source_set_cancel_handler(source, ^{ | 
|  | fprintf(stderr, "global = %ld\n", global); | 
|  |  | 
|  | dispatch_semaphore_signal(done); | 
|  | }); | 
|  |  | 
|  | dispatch_resume(source); | 
|  | dispatch_cancel(source); | 
|  |  | 
|  | dispatch_semaphore_wait(done, DISPATCH_TIME_FOREVER); | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | // CHECK: global = 42 |